Robin flicked the ash off his cigarette disdainfully.

"These promoted policemen make me tired," he said.

Bruce Wright shook his head quickly with a little gesture of exasperation.

"You don't understand," he said. "There's fresh evidence ..."

Robin Greve looked up with real interest in his eyes. His bantering manner had vanished.

"You've got that letter?" he asked eagerly.

Bruce shook his head.

"No, not that," he said. Then leaning forward he added in a low voice:

"Have you ever heard of the Maxim silencer?"

"I believe I have, vaguely," replied Robin. "Isn't it something to do with a motor engine?"

"No," said Bruce. "It's an extraordinary invention which absolutely suppresses the noise of the discharge of a gun."

Robin shot a quick glance at the speaker.

"Go on," he said.

"It's a marvelous thing, really," the boy continued, warming to his theme. "A man at Havre had one when I was at the base there, during the war. It's a little cup-shaped steel fitting that goes over the barrel.

You can fire a rifle fitted with one of these silencers in a small room and it makes no more noise than a fairly loud sneeze ..."

"Ah!"

Robin was listening intently now.

"Parrish had a Maxim silencer," Bruce went on impressively.

"_Parrish_ had?"

"It was fitted on his automatic pistol, the one he had in his hand when they found him ..."

"There was no attachment of any kind on the gun Parrish was holding when he was discovered yesterday afternoon," declared Robin positively; "I can vouch for that. I was there almost immediately after they found him.

And if there had been anything of the kind Horace Trevert would certainly have mentioned it ..."

"I know. Jay, who came in soon after you, was surprised to see that the silencer was not on the pistol. And he made a point of looking for it ..."

"But how do you know that Parrish had it on the pistol?..."

"Well, we don't know for certain. But we do know that it was permanently fitted to his automatic. Jay has often seen it. And if Parrish did remove it, he didn't leave it lying around any where. Jay has looked all through his things without finding it ..."

"When did Jay see it last?"

"On Thursday!"

"But are you sure that this is the same pistol as the one which Jay has been in the habit of seeing?"

"Jay is absolutely sure. He says that Parrish only had the one automatic which he always kept in the same drawer in his dressing-room ..."

Robin was silent for a moment. Very deliberately he filled his pipe, lit it, and drew until it burned comfortably. Then he said slowly:

"This means that Hartley Parrish was murdered, Bruce, old man. All through I have been puzzling my mind to reconcile the unquestionable circ.u.mstance that two bullets were fired--I told you of the bullet mark I found on the upright in the rosery--with the undoubted fact that only one report was heard. We can therefore presume, either that Hartley Parrish first fired one shot from his pistol with the silencer fitted and then removed the silencer and fired another shot without it, thereby killing himself, or that the second shot was fired by the person whose interest it was to get rid of the silencer. There is no possible or plausible reason why Parrish should have fired first one shot with the silencer and then one without. Therefore, I find myself irresistibly compelled to the conclusion that the shot heard by Mary Trevert was fired by the person who killed Parrish. Do I make myself clear?"

"Perfectly," answered Bruce.

"Now, then," the barrister proceeded, thoughtfully puffing at his pipe, "one weak point about my deductions is that they all hang on the question as to whether, at the time of the tragedy, Parrish actually had the silencer on his pistol or not. That is really the acid test of Manderton's suicide theory. You said, I think, that a rifle fired with the silencer attachment makes no more noise than the sound of a loud sneeze!"

"That's right," agreed Bruce; "a sort of harsh, spluttering noise. Not so loud either, Robin. Ph ... t-t-t! Like that!"

"Loud enough to be heard through a door, would you say?"

"Oh, I think so!"

Robin thought intently for a moment.

"Then Mary is the only one who can put us right on that point. a.s.suming that two shots were fired--and that bullet mark in the rosery is, I think, conclusive on that head--and knowing that she heard the loud report of the one, presumably, if Parrish had the silencer on his automatic, Mary must have heard the _m.u.f.fled_ report of the other. What it comes to is this, Mary heard the shot fired that killed Parrish. Did she hear the shot he fired at his murderer?"

"By Gad!" exclaimed Bruce Wright impressively, "I believe you've got it, Robin! Parrish fired at somebody at the window--a silent shot--and the other fellow fired back the shot that Mary Trevert heard, the shot that killed Parrish. Isn't that the way you figure it out?"

"Not so fast, young man," remarked Robin. "Let's first find out whether Mary actually heard the m.u.f.fled shot and, if so, _when ... before_ or _after_ the loud report."

He glanced across at the window and then at Bruce,

"I suppose this discovery about the silencer is responsible for the deputation waiting in the courtyard," he said drily.

"The police don't know about it yet," replied Bruce; "at least they didn't when I left."

Robin shook his head dubiously.

"If the servants know it, Manderton will worm it out of them. Hasn't he cross-examined Jay?"

"Yes," said Bruce. "But he got nothing out of him about this. Manderton seems to have put everybody's back up. He gets nothing out of the servants ..."

"If Parrish had had this silencer for some time, you may be sure that other people know about it. These silencers must be pretty rare in England. You see, an average person like myself didn't know what it was.

By the way, another point which we haven't yet cleared up is this: supposing we are right in believing Parrish to have been murdered, how do you explain the fact that the bullet removed from his body fitted his pistol?"

"That's a puzzler, I must say!" said Bruce.

"There's only one possible explanation, I think," Robin went on, "and that is that Parrish was shot by a pistol of exactly the same calibre as his own. For the murderer to have killed Parrish with his own weapon would have been difficult without a struggle. But Miss Trevert heard no struggle. For murderer and his victim to have pistols of the same calibre argues a rather remarkable coincidence, I grant you. But then life is full of coincidences! We meet them every day in the law. Though, I admit, this is a coincidence which requires some explaining ..."

He fell into a brown study which Bruce interrupted by suddenly remembering that he had had no lunch.

For answer Robin pointed at the sideboard.